Contraction Mapping/ Fixed Points/ Iterations

contraction mapping
phi x=((x^2)-2x+5)/4 with phi restricted to [0,2]

set up an iterative scheme with x0=1/2 converging to the fixed point of phi x inside [0,2]. give estimate on the maximum number of iterations needed to approach fixed point with error of less than 10^(-k) for any integer k??

how do i set up an iterative scheme converging to the fixed point? and then how do i find the maximum number of iterations needed?